Since you seems to be the only one requesting this functionality then I would say its not too much chance of it being implemented right now.

Can I suggest instead that you hide your adult entertainment deep down in a subfolder where no one would look.

IP-filtering in general is a feature that more than one persin has requested. Adding ip-filtering for each shared folders might be a way of solving it that also comply to your need. But most people wants ip-filtering so that the PMS dont show up at all in non-aproved PS3s.